这个插入语句有效。但是,我希望也许有人可以教我一种更有效的方法来执行此查询。这就是我所拥有的...
我有一个名为 Source 的表,其中 DealerID 是一个非唯一 ID(无论如何在该表中)。对于每个 DealerID,有多个 Name。示例:
15 BillBoard
15 Event
15 Newspaper
16 BillBoard
16 Event
16 Newspaper
我知道,我知道。这是存储这些数据的一种非常低效的方式。我们正在处理一个遗留应用程序,我现在无法彻底修改这个数据结构。所以,我需要做的是为每个 DealerID 添加两条新记录。一种用于“电话”,一种用于“互联网”。所以插入后,它看起来像这样:
15 BillBoard
15 Event
15 Newspaper
15 Phone
15 Internet
16 BillBoard
16 Event
16 Newspaper
16 Phone
16 Internet
下面的sql语句有效,但我想知道是否有更好的方法......
declare @SourceTemp table (
[Id] int identity (1, 1) not null,
[DealerId] int
)
insert into @SourceTemp select distinct DealerId from Source where DealerId is not null
declare @dealerid int
declare @rowcount int = 1
declare @idcount int
select @idcount = max(Id) from @SourceTemp
while @rowcount < (@idcount + 1)
begin
select @dealerid = DealerId from @SourceTemp where Id = @rowcount
---------------- Insert Phone
if not exists (select * from Source where DealerId = @dealerid and Name = 'Phone')
begin
insert into
Source
([DealerID],[Name],[Service],[CampaignCode],[Description],[Created],[UserCreated],[Active])
values
(@dealerid, 'Phone', 'Generic', 'CampaignCode', NULL, GETDATE(), 0, 1)
end
--------------- Insert Internet
if not exists (select * from Source where DealerId = @dealerid and Name = 'Internet')
begin
insert into
Source
([DealerID],[Name],[Service],[CampaignCode],[Description],[Created],[UserCreated],[Active])
values
(@dealerid, 'Internet', 'Generic', 'CampaignCode', NULL, GETDATE(), 0, 1)
end
set @rowcount = @rowcount + 1
end
编辑后:
我必须对汤姆的答案制作一个小模组,添加 DISTINCT。这有效...
INSERT INTO Source ([DealerID], [Name], [Service], [CampaignCode], [Description], [Created], [UserCreated], [Active])
SELECT DISTINCT
S.DealerId, SQ.Name, 'Generic', 'CampaignCode', NULL, GETDATE(), 0, 1
FROM
Source S
CROSS JOIN (SELECT 'Internet' AS Name UNION ALL SELECT 'Phone' AS Name) SQ
WHERE
NOT EXISTS (SELECT * FROM Source WHERE DealerID = S.DealerID AND Name = SQ.Name)
最佳答案
INSERT INTO Source (DealerID, Name, Service, CampaignCode, Description, ...)
SELECT DISTINCT
S.DealerID, SQ.Name, ...
FROM
Source S
CROSS JOIN (SELECT 'Internet' AS Name UNION ALL SELECT 'Phone' AS Name) SQ
WHERE
NOT EXISTS (SELECT * FROM Source WHERE DealerID = S.DealerID AND Name = SQ.Name)
更正了它以包含 DISTINCT,因为每个 DealerID
都会有多个其他 Name
。如果性能存在问题,那么您可以将 DISTINCT
向下移动到 Source
表上的子查询,然后从那里开始CROSS JOIN
:
INSERT INTO Source (DealerID, Name, Service, CampaignCode, Description, ...)
SELECT DISTINCT
S.DealerID, SQ.Name, ...
FROM
(SELECT DISTINCT DealerID
FROM Source
) S
CROSS JOIN (SELECT 'Internet' AS Name UNION ALL SELECT 'Phone' AS Name) SQ
WHERE
NOT EXISTS (SELECT * FROM Source WHERE DealerID = S.DealerID AND Name = SQ.Name)
关于sql - 重构循环 SQL 插入,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35297850/